1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to a cryogen recondensing system and a superconducting magnet apparatus including the same, and more particularly, to a cryogen recondensing system having an improved cryogen reservoir for recondensation of cryogen and a superconducting magnet apparatus including the same.
2. Description of the Related Art
A superconducting magnet apparatus, such as a magnetic resonance imaging (MRI) apparatus or a nuclear magnetic resonance (NMR) apparatus, uses a superconducting coil. Since the superconducting coil maintains a superconducting phenomenon at an extremely low temperature, such as 4.2 K, a cooling system is required to maintain such an extremely low temperature. A commercialized cooling system generally cools the superconducting coil using liquid helium.
On the other hand, in a superconducting magnet apparatus, such as an MRI apparatus, heat is generated from the cryogen reservoir or the superconducting coil due to Joule's heat caused by an eddy current during operation of the superconducting magnet apparatus, such as during MRI imaging. Liquid cryogen evaporates while cooling the heat and gas cryogen is stored in a cryogen reservoir, thereby increasing pressure within the cryogen reservoir. A recondensing cooling system is used in order to prevent the cryogen within the superconducting magnet apparatus from decreasing because of cryogen evaporation. The recondensing cooling system liquefies high-pressured gas cryogen stored in the cryogen reservoir using a refrigerator, thereby preventing a decrease in the amount of cryogen, within the superconducting magnet apparatus, through circulation between evaporation and liquefaction.
Since an existing thermosyphon type recondensing cooling system is required to be located in an upper portion of a superconducting coil, the size of a cryogen reservoir is limited. In addition, in order to store as much cryogen as possible in the cryogen reservoir, the amount of space for storing gas cryogen decreases. In order to resolve the space limitation of the cryogen reservoir, the cryogen reservoir protrudes upwardly from the superconducting magnet apparatus.